When l first began playing Kotor l downloaded one Mandalorian armor mod with tree style's(red,blue,yellow) but l equiped them on my character and when l started walking at the game footsteps began sounding like droid footsteps ??? does anyone knowns has an awnser ?

I don't think this is actually a bug. Most places the NPC Mandalorian's appear would be on soft ground, and the footsteps don't really sound like droids. But with the one that does appear elsewhere, Bendak, you can hear the droid footsteps when he leaves the Cantina.